I checked a few FATEs (310, 317), and it seems that a common attribute is that they are all returned with y: 0, while the z property seems to have the correct Y-value.
Example (310):
{
...
"map": {
...
"x": 29,
"y": 0,
"z": 25
},
"name": "Between Aurochs",
...
}
Having a look at GamerEscape's entry, you can indeed see that the correct coordinates are (29, 25); however, this should be returned as:
"x": 29,
"y": 25,
"z": 0 // zero, or the correct value